Enhancement of MT SM delivery for EDRX enabled mobile terminals

ABSTRACT

The invention relates to mobility management nodes and methods of the mobility management nodes of enabling delivery of a Mobile Terminating, (MT) Short Message (SM) to a mobile terminal.In a first aspect of the invention, a method of a mobility management node is provided for enabling delivery of a Mobile Terminating, (MT) Short Message (SM) to a mobile terminal which currently is in extended idle mode discontinuous reception, eDRX, mode. The method comprises receiving an indication from a Short Message Service Gateway Mobile Switching Centre (SMS-GMSC) that the SM is to be delivered, receiving a notification that the mobile terminal has exited an extended idle Discontinuous Reception (eDRX) mode before a paging occasion has occurred, and submitting, in response to the notification, a message indicating to the SMS-GMSC that the mobile terminal is available for delivery of the SM.

This application is a continuation of U.S. patent application Ser. No.16/774,619, filed Jan. 28, 2020, now U.S. Pat. No. 11,109,198, which isa continuation of U.S. patent application Ser. No. 15/771,054, filedApr. 25, 2018, now U.S. Pat. No. 10,595,170, which is a 35 U.S.C. § 371national phase filing of International Application No.PCT/EP2016/077871, filed Nov. 16, 2016, which claims the benefit of U.S.Provisional No. 62/262,006, filed Dec. 2, 2015, the disclosures of whichare incorporated herein by reference in their entireties.

TECHNICAL FIELD

The invention relates to mobility management nodes and methods of themobility management nodes of enabling delivery of a Mobile Terminating,(MT) Short Message (SM) to a mobile terminal.

The invention further relates to computer programs for causing themobility management nodes to perform the methods according to theinvention, and corresponding computer program products.

BACKGROUND

The Short Message Service (SMS) provides a means of sending messages oflimited size to and from mobile terminals in 3rd Generation PartnershipProject (3GPP) communications systems such as Global System for MobileCommunications (GSM), Universal Mobile Telecommunications System (UMTS)and Evolved Packet System (EPS). The provision of SMS makes use of aService Centre, which acts as a store and forward centre for shortmessages.

Mobile terminal originated messages are transported from a terminal tothe Service Centre, while mobile terminated messages shall betransported from the Service Centre to a terminal. Short messages aretypically input to the Service Centre by other mobile users, and aredestined for other mobile users, or for subscribers on a fixed network.This is described in detail in Technical Specification 3GPP TS 23.040.

Now, for extending battery lifetime of a mobile terminal, a method knownas Discontinuous Reception (DRX) is used where the mobile terminal,oftentimes referred as a User Equipment (UE), only occasionally monitorsa Physical Downlink Control Channel (PDCCH) to check if there isdownlink data available.

Recently introduced UE types, such as Machine Type Communications (MTC)devices, require extremely efficient power saving, which has led to theintroduction of a mode referred to as extended idle mode DRX (eDRX).That is, the UE and the network may negotiate over Non-Access Stratum(NAS) signaling the use of extended idle mode DRX for reducing its powerconsumption, while being available for mobile terminating data and/ornetwork originated procedures within a certain delay dependent on theDRX cycle value. An eDRX enabled UE can only be reachable by the network(i.e. be paged by the network) during its paging transmission window(PTW), and during that window, the UE uses normal DRX.

In “MT SMS procedures for UEs in extended idle mode DRX”, C4-152115,3GPP TSG CT4 Meeting #71, Anaheim, USA; 16-20 Nov. 2015, it is describeda mobile terminated (MT) short message (SM) delivery from a ShortMessage Service Centre (SMSC) to a Mobility Management Entity (MME).

Reference is made to the timing diagram of enclosed FIG. 1 .

-   -   1. The SMSC submits a Send-Routing-Info-for-SM-Request (SRR)        command to a Home Subscriber Server (HSS) to retrieve the        address of the nodes serving the UE.    -   2. The HSS replies accordingly by submitting a        Send-Routing-Info-for-SM-Answer (SRA) message, indicating the        address of the serving MME.    -   3. The SMSC sends an MT-Forward-Short-Message-Request (TFR) to        the serving MME. The SMSC indicates in the TFR a Max        Retransmission Time (e.g. 5 to 10 minutes), which indicates for        how long the SMSC is ready to store the SM if it cannot be        delivered at once due to the UE being in extended idle mode DRX.    -   4. If the UE is reachable within the Max Retransmission Time        provided in the TFR, the MME immediately sends an        MT-Forward-Short-Message-Request-Answer (TFA) in step 4a        indicating Requested Retransmission Time, i.e. the time at which        the SM should be resent by the SMSC. The MME also pages the UE        in 4b.    -   At this stage, the SMSC will not send a        Report-SM-Delivery-Status-Request (RDR) to the HSS with the        indication that the SM delivery was unsuccessful. Consequently,        the HSS will not reply with a Report-SM-Delivery-Status-Answer        (RDA) message, and will not store the Service Centre address in        its Message Waiting Data (MWD).    -   5. The UE responds to the paging at which point in time a        signalling connection is established between the UE and the MME.    -   At this stage, the MME does not send a Notify-Request (NOR) to        the HSS to signal that the UE has become reachable.    -   6. The SMSC retransmits the SM at the Requested Retransmission        Time which was indicated in the TFA (no Max Retransmission Time        is included in this second transmission of the TFR).

The solution in “MT SMS procedures for UEs in extended idle mode DRX” isdescribed to present the following merits:

a. MT SM for UEs in eDRX does not cause any extra HSS signalling.

b. No issue with short eDRX period (e.g. up to 20 s) of synchronizationof messages received at HSS.

c. Single-attempt-delivery SM can be transmitted to the UE if thisprocedure is used (without the need to use MWD forsingle-attempt-delivery SM as previously has been specified).

The solution in “MT SMS procedures for UEs in extended idle mode DRX” isfurther described to present the following drawbacks:

a. SM retransmission is triggered without knowing for certain whetherthe UE indeed is reachable (e.g. the UE may have detached, the UE may bein a tunnel, the eDRX period may have been renegotiated, etc.).

b. Greater impact on SMSC (extended buffering of MT-SM e.g. for up to5-10 min).

c. The Mobile Station Not Reachable Flag (MNRF) flag is not set in theHSS, so subsequent MT SM to the same UE from a different SMSC willtrigger new MT Forward SM Request to MME for UEs which are unreachable.

d. Introduces a further method to deliver MT SMS for UEs using extendedidle mode DRX.

The applicant has identified further drawbacks with this solution aswill be discussed with reference to FIG. 2 .

As in FIG. 1 , the SMSC submits a TFR to the currently serving MME(MME1) to indicate that an SM is to be submitted to the UE. The TFRincludes a Max Retransmission Time indicating how long the SMSC is readyto store the SM if it cannot be delivered at once due to the UE being ineDRX.

MME1 correspondingly replies with a TFA indicating RequestedRetransmission Time at which the SM should be retransmitted by the SMSC,and will subsequently page the UE at a next paging occasion occurringjust shortly before beginning of a next Paging Transmission Window, i.e.just before the indicated Requested Retransmission Time, such that theSM can be timely delivered from the SMSC via MME 1 to the UE when the UEwakes of from its eDRX cycle at the Requested Retransmission Time.

Now, a first problem arises if the UE wakes up from its eDRX cycle, thusexiting eDRX mode, for instance due to a UE service request for sendingdata, and correspondingly initiates NAS signalling towards its currentlyserving mobility management node, e.g. an MME or a Serving GPRS (GeneralPacket Radio Service) Support Node (SGSN), before having been paged bythe serving mobility management node, in this particular example MME1.

NAS signalling is used to convey non-radio signalling between the UE andthe MME for a Long Term Evolution/Evolved Universal Terrestrial AccessNetwork (LTE/E-UTRAN) access. For instance, a NAS request may be aRouting Area Update (RAU) request which updates the location of the UEwithin the network. A UE initiates a RAU when it detects that it entersa new Routing Area, and thus it will contact the core network, eitherthe current serving SGSN or a new SGSN.

Hence, the first problem can be exemplified as occurring in case of anintra SGSN RAU request, i.e. when the UE enters a new Routing Area, butis to remain at the serving SGSN, exemplified in FIG. 2 by SGSN1. Whenthe SMSC attempts to submit the SM to the UE at the TFA specifiedRequested Retransmission Time, there is a risk that the UE again hasentered eDRX mode, and the scheduled MT-SMS delivery will consequentlyfail. When UE is camping in UTRAN, the eDRX cycle will restart at eachRouting Area Update procedure.

When the UE is camping in E-UTRAN and GSM, the paging occasion schemecan be maintained, if the serving MME or SGSN would maintain the eDRXcycle regardless of whether the UE requests to change the eDRX cycle atthe TAU/RAU. In this scenario, the issue is less troublesome, but theMT-SMS is nevertheless unnecessarily delayed until the next scheduledpaging time, extra signalling is required towards the UE, and UE powerconsumption increases, which indeed should be avoided.

Further, a second problem arises if the UE initiates a NAS requesttowards another mobility management node, thereby effecting an idle modemobility procedure between two management nodes referred to as an interMME TAU request, the other node being exemplified by MME2 in FIG. 2 ,before the UE has responded to the paging message from the network. Thatis, the paging message has not been sent by the first mobilitymanagement node since the paging window has not yet occurred.

This would e.g. occur if the UE initiates the MME TAU request after MME1has reported the Requested Retransmission Time to the SMSC indicating anext paging occasion based on the eDRX cycle, but before the actualpaging occasion occurs.

In this case, the SMSC would deliver the MT-SMS to the wrong MME, i.e.MME1, at the TFA specified Requested Retransmission Time.

SUMMARY

An object of the invention is to solve, or at least mitigate, at leastone of these problems in the art and thus to provide improved methods offacilitating delivery of Short Messages to a mobile terminal enabled foreDRX mode.

This object is attained in a first aspect of the invention by a methodof a mobility management node of enabling delivery of a MobileTerminating, (MT) Short Message (SM) to a mobile terminal, whichcurrently is in eDRX mode. The method comprises receiving an indicationfrom a Short Message Service Gateway Mobile Switching Centre (SMS-GMSC)that the SM is to be delivered, receiving a notification that the mobileterminal has exited the eDRX mode before a paging occasion has occurred,and submitting, in response to the notification, a message indicating tothe SMS-GMSC that the mobile terminal is available for delivery of theSM.

This object is attained in a second aspect of the invention by amobility management node configured to enable delivery of an MT SM, to amobile terminal which currently is in extended eDRX mode, and whichmobility management node comprises a processing unit and a memory, saidmemory containing instructions executable by said processing unit,whereby said mobility management node is operative to receive anindication from an SMS-GMSC that the SM is to be delivered, receive anotification that the mobile terminal has exited the eDRX mode before apaging occasion has occurred, submit, in response to the notification, amessage indicating to the SMS-GMSC that the mobile terminal sisavailable for delivery of the SM.

This object is attained in a third aspect of the invention by a methodof a mobility management node of enabling delivery of an MT SM to amobile terminal which currently is in eDRX mode, comprising receiving anotification that the mobile terminal has exited the eDRX mode before apaging occasion has occurred, submitting a context request to anothermobility management node by which the mobile terminal was served beforethe notification was received, receiving from said another mobilitymanagement node a context response comprising an indication that the SMis to be delivered; and receiving, from the SMS-GMSC, the SM fordelivery to the mobile terminal.

This object is attained in a fourth aspect of the invention by amobility management node configured to enable delivery of an MT SM to amobile terminal which currently is in eDRX mode, and which mobilitymanagement node comprises a processing unit and a memory, said memorycontaining instructions executable by said processing unit, whereby saidmobility management node is operative to receive a notification that themobile terminal has exited the eDRX mode before a paging occasion hasoccurred, submit a context request to another mobility management nodeby which the mobile terminal was served before the notification wasreceived, receive, from said another mobility management node, a contextresponse comprising an indication that the SM is to be delivered, andreceive, from the SMS-GMSC, the SM for delivery to the mobile terminal.

In an embodiment, the message is submitted directly to the SMS-GMSC. Inanother embodiment, the message is submitted to the SMS-GMSC via a HomeSubscription Server (HSS).

In an embodiment, the message submitted to the SMS-GMSC via the HSSfurther comprises an instruction to the HSS to provide the destinationaddress of the mobility management to the SMS-GMSC.

In still another embodiment, the notification is a Non-Access Stratum(NAS) request received from the mobile terminal.

In still an embodiment, the notification is a context request receivedfrom a serving mobility management node of the mobile terminal, and themethod further comprises submitting, to the serving mobility managementnode, a context response comprising an indication that the SM is to bedelivered, and receiving, from the serving mobility management node, acontext acknowledgement comprising a destination address of the servingmobility management node for SM delivery, wherein said submitted messagefurther comprises the destination address of the serving mobilitymanagement node.

In another embodiment, the notification is a context request receivedfrom a serving mobility management node of the mobile terminal, saidmessage being submitted to the SMS-GSMC via the serving mobilitymanagement node in a context response and further comprising adestination address of the SMS-GSMC.

In still an embodiment, the receiving of an indication from a SMS-GMSCthat the SM is to be delivered comprises receiving an indication ofmaximum retransmission time specifying how long the SMS-GMSC will storethe SM if it cannot be delivered at once and capability indicationindicating if the SMS-GMSC support receiving subsequent notification ofmobile terminal availability for delivering the SM, the method furthercomprising submitting an indication to the SMS-GMSC comprising arequested retransmission time indicating at which point in time the SMshould be retransmitted by the SMS-GMSC and capability confirmation thatthe mobility management node supports the subsequent notification ofmobile terminal availability for delivering the SM.

In a further embodiment, the message submitted further indicates a timeperiod specifying the time up until the mobile terminal again enters theeDRX mode.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 shows a prior art timing diagram illustrating an MT SM deliveryfrom an SMSC to an MME;

FIG. 2 shows a timing diagram illustrating problems related to the MT SMdelivery procedure of FIG. 1 ;

FIG. 3 illustrates an embodiment of a method of the invention;

FIG. 4 illustrates another embodiment of a method of the invention;

FIG. 5 illustrates yet another embodiment of a method of the invention;

FIG. 6 illustrates still another embodiment of a method of theinvention;

FIG. 7 illustrates yet a further embodiment of a method of theinvention;

FIG. 8 illustrates still a further embodiment of a method of theinvention;

FIG. 9 illustrates another embodiment of a method of the invention;

FIG. 10 illustrates yet another embodiment of a method of the invention;

FIG. 11 illustrates embodiments of a mobility management node of theinvention; and

FIG. 12 illustrates further embodiment of a mobility management node ofthe invention.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter withreference to the accompanying drawings, in which certain embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided byway of example so that this disclosure will be thorough and complete,and will fully convey the scope of the invention to those skilled in theart. Like numbers refer to like elements throughout the description.

FIG. 1 shows a timing diagram illustrating an MT SM delivery from anSMSC to an MME disclosed in “MT SMS procedures for UEs in extended idlemode DRX”, as previously discussed.

FIG. 2 shows a timing diagram illustrating problems related to the MT SMdelivery procedure of FIG. 1 , as previously has been discussed. TheSMSC will in the following be referred to as a Short Message ServiceGateway Mobile Switching Centre (SMS-GMSC).

In short, a first problem arises if the UE 10 wakes up from an eDRXcycle, i.e. it exits an eDRX mode in which it has been residing, beforea next paging occasion takes place. The SMS-GMSC 40 has been scheduledfor SM delivery at the next paging occasion, and will thus miss theopportunity to deliver the SM to the UE 10 exiting the eDRX mode viaMME1/SGSN1 20; once the next paging occasion occurs, there is a riskthat the UE 10 again has entered eDRX mode, resulting in another SMdelivery failure, and the procedure must be repeated.

Further, a second problem arises if the UE 10 exits an eDRX mode inwhich it has been residing before a next paging occasion takes place, inthis scenario by performing e.g. an inter MME TAU. In such a scenario,when the SMS-GMSC 40 is scheduled for SM delivery at the next pagingoccasion, the SMS-GMSC 40 will deliver the SM to MME1/SGSN1 20, which nolonger is the serving MME, instead of delivering the SM to MME2/SGSN230.

In the following, MME1/SGSN1 and MME2/SGSN2 will be referred to MME1 andMME2, respectively. However, it should be noted that they embodymobility management nodes of both UTRAN and E-UTRAN.

FIG. 3 illustrates an embodiment of a method of the invention performedat MME1 20 of enabling delivery of an MT SM from the SMS-GMSC 40 to theUE 10.

In a first step S101, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10, which currently is ineDRX mode. Now, if the UE 10 exits the eDRX mode, for instance as aconsequence of a NAS request for intra MME TAU, intra SGSN RAU, or ageneral Service Request, etc., before a paging occasion has occurred,MME1 20 will receive a notification accordingly in a second step S102.

In a third step S103, MME1 20 submits to the SMS-GMSC 40, in response tothe indication received in step S102, a message indicating that the UE10 is available for immediate delivery of the SM. As a result, theSMS-GMSC will advantageously not miss out on the opportunity to deliverthe SM to the UE 10, which is currently not in eDRX mode, in step S104via MME1 20.

In an alternative embodiment, the message is not submitted directly tothe SMS-GMSC 40, but via an HSS (not shown in FIG. 3 ). In suchembodiment, the message submitted to the SMS-GMSC 40 via the HSS furthercomprises an instruction to the HSS to provide the destination addressof MME1 20 (which is known to the HSS) to the SMS-GMSC 40, in order forthe SMS-GSMC 40 to be able to deliver the SM to the UE 10 via MME1 20.

FIG. 4 illustrates an embodiment of a method of the invention ofenabling delivery of an MT SM from the SMS-GMSC 40 to the UE 10.

In a first step S101, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10, which currently is ineDRX mode. Now, if the UE 10 exits the eDRX mode, for instance as aconsequence of a NAS request in step S102 a for TAU, RAU, or a generalService Request, etc., to an MME2 30 before a paging occasion hasoccurred, the other MME1 20 will receive a notification accordingly.However, in contrast to the embodiment described with reference to FIG.3 , the notification is in this scenario not received from the UE 10,but from MME2 (now being the serving MME) in the form of a ContextRequest in step S102 b.

As a consequence, MME1 20 submits a Context Response in step S102 c tobe received by MME2 30 and comprising an indication that the SM is to bedelivered. In response thereto, MME1 20 receives a ContextAcknowledgement sent by MME2 in step S102 d and comprising a destinationaddress of the new serving MME, i.e. MME2 30, for subsequent SMdelivery.

In step S103, MME1 20 submits to the SMS-GMSC 40, in response to thenotification received in step S102 b, a message indicating that the UE10 is available for immediate delivery of the SM, which message in thisembodiment further comprises the destination address of MME2 30 beingthe serving MME.

As a result, the SMS-GMSC 40 will advantageously deliver the SM to thecorrect MME in step S105, i.e. to MME2 30, and further on to the UE 10,which is currently not in eDRX mode.

With reference again to FIG. 4 , in an alternative embodiment, thenotification of the UE 10 having exited eDRX mode is again received inthe form of a context request in step S102 b from MME2 30. However, themessage indicating that the SM can be delivered immediately to the UE 10is submitted in step S103 a to the SMS-GSMC 40 via MME2 30 in theContext Response in step S102 c, which message in this embodimentfurther comprises a destination address of the SMS-GSMC 40 for theinformation of MME2 30.

It may, similar to the embodiment discussed with reference to FIG. 4 ,be envisaged in an embodiment that the message is not submitted directlyto the SMS-GMSC 40, but via an HSS (not shown in FIG. 4 ). In suchembodiment, the message submitted to the SMS-GMSC 40 via the HSS furthercomprises an instruction to the HSS to provide the destination addressof MME2 30 to the SMS-GMSC 40, in order for the SMS-GSMC 40 to be ableto deliver the SM to the UE 10 via the correct MME, i.e. MME2 30.

With reference to FIGS. 3 and 4 , it can be envisaged in embodimentsthat step S101, where MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10, which currently is ineDRX mode, is expanded to include steps 101 a and 101 b of FIG. 5 to bedescribed in the following.

FIG. 5 illustrates an embodiment of the invention performed at MME1 20of enabling delivery of an MT SM from the SMS-GMSC 40 to the UE 10 basedon the embodiment previously discussed with reference to FIG. 3 .

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10 in the form of a TFRincluding a Max Retransmission Time, which indicates how long theSMS-GMSC 40 will store the SM if it cannot be delivered at once, andfurther a capability indication indicating if the SMS-GMSC 40 supportreceiving subsequent notification of UE availability for delivering theSM.

Thereafter, in step S101 b, MME1 20 responds with a TFA indicatingRequested Retransmission Time, i.e. the time at which the SM should beretransmitted by the SMS-GMSC 40 since the UE 10 currently is in an eDRXmode. The TFA further indicates whether MME1 supports subsequentnotification of UE availability for delivering the SM when the UE 10exits eDRX mode.

As previously has been described, if the UE 10 exits the eDRX mode, forinstance as a consequence of a NAS request for intra MME TAU, intra SGSNRAU, or a general Service Request, etc., before a paging occasion hasoccurred, MME1 20 will receive a notification accordingly in step S102.

In a step S103, MME1 20 submits to the SMS-GMSC 40, in response to theindication received in step S102, a message indicating that the UE 10 isavailable for immediate delivery of the SM. As a result, the SMS-GMSCwill advantageously not miss out on the opportunity to deliver the SM tothe UE 10, which is currently not in eDRX mode, in step S104 via MME120.

Optionally, for all embodiments of the invention, the message includes aMaximum-UE-Availability-Time, i.e. a time period specifying the time upuntil the UE 10 again enters the eDRX mode, thereby advantageouslyindicating a time window during which the UE 10 will be available for SMdelivery.

As can be seen in FIG. 5 , the submission in step S103 either uses anexisting message such as an OFR, or a new Diameter message. The SMS-GMSC40 acknowledges the message in step S104 a correspondingly using anexisting message such as an OFA, or a new Diameter message.

The pending SM is delivered by the SMS-GMSC 40 in the TFR of step S104,and MME1 acknowledges the delivery accordingly with a TFA in step S106.

FIG. 6 illustrates an embodiment of the invention performed at MME1 20of enabling delivery of an MT SM from the SMS-GMSC 40 to the UE 10 basedon an embodiment previously discussed with reference to FIG. 4 .

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10 in the form of a TFRincluding a Max Retransmission Time, which indicates how long theSMS-GMSC 40 will store the SM if it cannot be delivered at once, andfurther a capability indication indicating if the SMS-GMSC 40 supportreceiving subsequent notification of UE availability for delivering theSM.

Thereafter, in step S101 b, MME1 20 responds with a TFA indicatingRequested Retransmission Time, i.e. the time at which the SM should beretransmitted by the SMS-GMSC 40 since the UE 10 currently is in an eDRXmode. The TFA further indicates whether MME1 supports subsequentnotification of UE availability for delivering the SM when the UE 10exits eDRX mode.

As previously has been described, if the UE 10 exits the eDRX mode, forinstance as a consequence of a NAS request for intra MME TAU, intra SGSNRAU, or a general Service Request, etc., before a paging occasion hasoccurred, MME1 20 will receive a notification accordingly in a secondstep S102.

In step S103 b, MME1 20 submits to the SMS-GMSC 40, via the HSS 50, inresponse to the indication received in step S102, a message indicatingthat the UE 10 is available for immediate delivery of the SM. Themessage may be submitted e.g. in the form of an Update Location Request(ULR) or Notify-Request (NOR) and includes an instruction to the HSS 50to subsequently provide the destination address of MME1 20 to theSMS-GMSC 40.

The HSS 50 responds accordingly in step S103 c with an acknowledgementin the form of e.g. a Update Location Answer (ULA) or Notify-Answer(NOA), and sends in step S103 d the message indicating UE availabilityand address of MME1 20 in an Alert-Service-Centre-Request (ALR). TheSMS-GMSC thus sends an acknowledgement Alert-Service-Centre-Answer (ALA)in step S103 e to the HSS 50.

Optionally, the message in S103 b and S103 d includes aMaximum-UE-Availability-Time, i.e. a time period specifying the time upuntil the UE 10 again enters the eDRX mode, thereby advantageouslyindicating a time window during which the UE 10 will be available for SMdelivery.

The pending SM is delivered by the SMS-GMSC 40 in the TFR of step S104,and MME1 acknowledges the delivery accordingly with a TFA in step S106.As a result, the SMS-GMSC 40 will advantageously not miss out on theopportunity to deliver the SM to the UE 10, which is currently not ineDRX mode, in step S104 via MME1 20.

FIG. 7 illustrates an embodiment of the invention of enabling deliveryof an MT SM from the SMS-GMSC 40 to the UE 10 based on an embodimentpreviously discussed with reference to FIG. 4 .

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10 in the form of a TFRincluding a Max Retransmission Time, which indicates how long theSMS-GMSC 40 will store the SM if it cannot be delivered at once, andfurther a capability indication indicating if the SMS-GMSC 40 supportreceiving subsequent notification of UE availability for delivering theSM.

Thereafter, in step S101 b, MME1 20 responds with a TFA indicatingRequested Retransmission Time, i.e. the time at which the SM should beretransmitted by the SMS-GMSC 40 since the UE 10 currently is in an eDRXmode. The TFA further indicates whether MME1 supports subsequentnotification of UE availability for delivering the SM when the UE 10exits eDRX mode.

If the UE 10 exits the eDRX mode, for instance as a consequence of a NASrequest in step S102 a for TAU, RAU, or a general Service Request, etc.,to MME2 30 before a paging occasion has occurred, MME1 20 will receive anotification accordingly from MME2 30 (now being the serving MME) in theform of a Context Request in step S102 b.

As a consequence, MME1 20 submits a Context Response in step S102 c toMME2 30 comprising an indication that the SM is to be delivered, whichmessage in this embodiment further comprises a destination address ofthe SMS-GSMC 40 for the information of MME2 30. In response thereto,MME2 30 transmits a Context Acknowledgement in step S102 d to MME1 20.

In step S103 a, MME2 30 submits to the SMS-GMSC 40, in response to theindication received in step S102 c, a message indicating that the UE 10is available for immediate delivery of the SM. As a result, the SMS-GMSC40 will advantageously deliver the SM to the correct MME in step S105,i.e. to MME2 30, and further on to the UE 10, which is currently not ineDRX mode.

Optionally, the message includes a Maximum-UE-Availability-Time, i.e. atime period specifying the time up until the UE 10 again enters the eDRXmode, thereby advantageously indicating a time window during which theUE 10 will be available for SM delivery.

As can be seen in FIG. 7 , the submission in step S103 a either uses anexisting message such as an OFR, or a new Diameter message. The SMS-GMSC40 acknowledges the message in step S105 a correspondingly using anexisting message such as an OFA, or a new Diameter message.

The pending SM is delivered by the SMS-GMSC 40 in the TFR of step S105,and MME2 30 acknowledges the delivery accordingly with a TFA in stepS106 a.

FIG. 8 illustrates an embodiment of the invention of enabling deliveryof an MT SM from the SMS-GMSC 40 to the UE 10 related to that previouslydiscussed with reference to FIG. 7 .

However, in this particular embodiment, the message indicating UEavailability for SM delivery is sent by MME2 30 to the SMS-GSMC 40 viathe HSS 50.

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10 in the form of a TFRincluding a Max Retransmission Time, which indicates how long theSMS-GMSC 40 will store the SM if it cannot be delivered at once, andfurther a capability indication indicating if the SMS-GMSC 40 supportreceiving subsequent notification of UE availability for delivering theSM.

Thereafter, in step S101 b, MME1 20 responds with a TFA indicatingRequested Retransmission Time, i.e. the time at which the SM should beretransmitted by the SMS-GMSC 40 since the UE 10 currently is in an eDRXmode. The TFA further indicates whether MME1 supports subsequentnotification of UE availability for delivering the SM when the UE 10exits eDRX mode.

If the UE 10 exits the eDRX mode, for instance as a consequence of a NASrequest in step S102 a for TAU, RAU, or a general Service Request, etc.,to MME2 30 before a paging occasion has occurred, MME1 20 will receive anotification accordingly from MME2 30 (now being the serving MME) in theform of a Context Request in step S102 b.

As a consequence, MME1 20 submits a Context Response in step S102 c toMME2 30 comprising an indication that the SM is to be delivered, whichmessage in this embodiment further comprises a destination address ofthe SMS-GSMC 40 for the information of MME2 30. In response thereto,MME2 30 transmits a Context Acknowledgement in step S102 d to MME1 20.

In step S103 f, MME2 30 submits to the SMS-GMSC 40, via the HSS 50, inresponse to the indication received in step S102 c, a message indicatingthat the UE 10 is available for immediate delivery of the SM. Themessage may be submitted e.g. in the form of an ULR or NOR and includesan instruction to the HSS 50 to subsequently provide the destinationaddress of MME2 30 to the SMS-GMSC 40.

The HSS 50 responds accordingly in step S103 g with an acknowledgementin the form of e.g. a ULA or NOA, and sends in step S103 h the messageindicating UE availability and address of MME2 30 in an ALR. TheSMS-GMSC 40 thus sends an acknowledgement (ALA) in step S103 i to theHSS 50.

Optionally, the message in steps S103 f and S103 h includes aMaximum-UE-Availability-Time, i.e. a time period specifying the time upuntil the UE 10 again enters the eDRX mode, thereby advantageouslyindicating a time window during which the UE 10 will be available for SMdelivery.

The SMS-GMSC 40 will advantageously deliver the SM to the correct MME instep S105, i.e. to MME2 30, and further on to the UE 10, which iscurrently not in eDRX mode, and MME2 30 acknowledges the deliveryaccordingly with a TFA in step S106 a.

FIG. 9 illustrates an embodiment of the invention of enabling deliveryof an MT SM from the SMS-GMSC 40 to the UE 10 based on an embodimentpreviously discussed with reference to FIG. 4 .

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10. Preferably the indicationis in the form of a TFR including a Max Retransmission Time, whichindicates how long the SMS-GMSC 40 will store the SM if it cannot bedelivered at once. The indication may further include a capabilityindication indicating if the SMS-GMSC 40 support receiving subsequentnotification of UE availability for delivering the SM.

Thereafter, in step S101 b, MME1 20 responds to the SMS-GMSC 40,preferably with a TFA indicating Requested Retransmission Time, i.e. thetime at which the SM should be retransmitted by the SMS-GMSC 40 sincethe UE 10 currently is in an eDRX mode. The TFA may further indicatewhether MME1 supports subsequent notification of UE availability fordelivering the SM when the UE 10 exits eDRX mode.

If the UE 10 exits the eDRX mode, for instance as a consequence of a NASrequest in step S102 a for TAU, RAU, or a general Service Request, etc.,to an MME2 30 before a paging occasion has occurred, the other MME1 20will receive a notification accordingly from MME2 30 (now being theserving MME) in the form of a Context Request in step S102 b.

As a consequence, MME1 20 submits a Context Response in step S102 c toMME2 30 comprising an indication that the SM is to be received by MME230. In response thereto, MME2 30 transmits a Context Acknowledgement instep S102 d to MME1 20 comprising a destination address of MME2 30.

In step S103, MME1 20 submits to the SMS-GMSC 40 a message indicatingthat the UE 10 is available for immediate delivery of the SM, and thedestination address of MME2 30. As a result, the SMS-GMSC 40 willadvantageously deliver the SM to the correct MME in step S104, i.e. toMME2 30, and further on to the UE 10, which is currently not in eDRXmode.

Optionally, the message includes a Maximum-UE-Availability-Time, i.e. atime period specifying the time up until the UE 10 again enters the eDRXmode, thereby advantageously indicating a time window during which theUE 10 will be available for SM delivery.

As can be seen in FIG. 9 , the submission in step S103 either uses anexisting message such as an OFR, or a new Diameter message. The SMS-GMSC40 acknowledges the message in step S104 a correspondingly using anexisting message such as an OFA, or a new Diameter message.

The pending SM is delivered by the SMS-GMSC 40 in the TFR of step S105,and MME2 30 acknowledges the delivery accordingly with a TFA in stepS106 a.

FIG. 10 illustrates an embodiment of the invention of enabling deliveryof an MT SM from the SMS-GMSC 40 to the UE 10 related to that previouslydiscussed with reference to FIG. 9 .

However, in this particular embodiment, the message indicating UEavailability for SM delivery is sent by MME1 20 to the SMS-GSMC 40 viathe HSS 50.

In a first step S101 a, MME1 20 receives an indication from the SMS-GMSC40 that an SM is to be delivered to the UE 10 in the form of a TFRincluding a Max Retransmission Time, which indicates how long theSMS-GMSC 40 will store the SM if it cannot be delivered at once, andfurther a capability indication indicating if the SMS-GMSC 40 supportreceiving subsequent notification of UE availability for delivering theSM.

Thereafter, in step S101 b, MME1 20 responds with a TFA indicatingRequested Retransmission Time, i.e. the time at which the SM should beretransmitted by the SMS-GMSC 40 since the UE 10 currently is in an eDRXmode. The TFA further indicates whether MME1 supports subsequentnotification of UE availability for delivering the SM when the UE 10exits eDRX mode.

If the UE 10 exits the eDRX mode, for instance as a consequence of a NASrequest in step S102 a for TAU, RAU, or a general Service Request, etc.,to MME2 30 before a paging occasion has occurred, MME1 20 will receive anotification accordingly from MME2 30 (now being the serving MME) in theform of a Context Request in step S102 b.

As a consequence, MME1 20 submits a Context Response in step S102 c toMME2 30 comprising an indication that the SM is to be delivered. Inresponse thereto, MME2 30 transmits a Context Acknowledgement in stepS102 d to MME1 20 comprising a destination address of MME2 30.

In step S103 b, MME1 20 submits to the SMS-GMSC 40, via the HSS 50, amessage indicating that the UE 10 is available for immediate delivery ofthe SM. The message may be submitted e.g. in the form of an ULR or NORand includes an instruction to the HSS 50 to subsequently provide thedestination address of MME2 30 to the SMS-GMSC 40.

The HSS 50 responds accordingly in step S103 c with an acknowledgementin the form of e.g. a ULA or NOA, and sends in step S103 d the messageindicating UE availability and address of MME2 30 in an ALR. TheSMS-GMSC 40 thus sends an acknowledgement (ALA) in step S103 e to theHSS 50.

Optionally, the message in S103 b and S103 d includes aMaximum-UE-Availability-Time, i.e. a time period specifying the time upuntil the UE 10 again enters the eDRX mode, thereby advantageouslyindicating a time window during which the UE 10 will be available for SMdelivery.

The SMS-GMSC 40 will advantageously deliver the SM to the correct MME instep S105, i.e. to MME2 30, and further on to the UE 10, which iscurrently not in eDRX mode, and MME2 30 acknowledges the deliveryaccordingly with a TFA in step S106 a.

With reference to Figure ii, the steps of the methods performed by themobility management nodes 20, 30 according to embodiments of theinvention are in practice performed by a processing unit 21, 31 embodiedin the form of one or more microprocessors arranged to execute acomputer program 22, 32 downloaded to a suitable storage medium 23, 33associated with the microprocessor, such as a Random Access Memory(RAM), a Flash memory or a hard disk drive. The processing unit 21, 31is arranged to cause the computing device 20, 30 to carry out the methodaccording to embodiments of the present invention when the appropriatecomputer program 22, 32 comprising computer-executable instructions isdownloaded to the storage medium 23, 33 and executed by the processingunit 21, 31. The storage medium 23, 33 may also be a computer programproduct comprising the computer program 22, 32. Alternatively, thecomputer program 22, 32 may be transferred to the storage medium 23, 33by means of a suitable computer program product, such as a DigitalVersatile Disc (DVD) or a memory stick. As a further alternative, thecomputer program 22, 32 may be downloaded to the storage medium 23, 33over a network. The processing unit 21, 31 may alternatively be embodiedin the form of a digital signal processor (DSP), an application specificintegrated circuit (ASIC), a field-programmable gate array (FPGA), acomplex programmable logic device (CPLD), etc.

FIG. 12 illustrates a first mobility management node 20 according to anembodiment of the invention configured to enable delivery of an MT SM toa mobile terminal. The mobility management node 20 comprises receivingmeans 24 adapted to receive an indication from an SMS-GMSC that the SMis to be delivered, receiving means 25 adapted to receive a notificationthat the mobile terminal has exited an eDRX mode before a pagingoccasion has occurred, and submitting means 26 adapted to submit, inresponse to the notification, a message indicating to the SMS-GMSC thatthe mobile terminal is available for delivery of the SM.

The means 24-26 may comprise a communications interface for receivingand providing information, and further a local storage for storing data,and may (in analogy with the description given in connection to FIG. 11) be implemented by a processor embodied in the form of one or moremicroprocessors arranged to execute a computer program downloaded to asuitable storage medium associated with the microprocessor, such as aRAM, a Flash memory or a hard disk drive.

FIG. 12 illustrates a second mobility management node 30 according to anembodiment of the invention configured to enable delivery of an MT SM toa mobile terminal. The mobility management node 30 comprises receivingmeans 34 adapted to receive a notification that the mobile terminal hasexited an eDRX mode before a paging occasion has occurred submittingmeans 35 adapted to submit a context request to another mobilitymanagement node by which the mobile terminal was served before thenotification was received, receiving means 36 adapted to receive, fromsaid another mobility management node, a context response comprising anindication that the SM is to be delivered and a destination address ofan SMS-GMSC delivering the SM, and submitting means 37 adapted tosubmit, in response to the context response, a message indicating to theSMS-GMSC that the mobile terminal is available for delivery of the SM.

The means 34-37 may comprise a communications interface for receivingand providing information, and further a local storage for storing data,and may (in analogy with the description given in connection to FIG. 11) be implemented by a processor embodied in the form of one or moremicroprocessors arranged to execute a computer program downloaded to asuitable storage medium associated with the microprocessor, such as aRAM, a Flash memory or a hard disk drive.

Some embodiments described above may be summarised in the followingmanner:

A first embodiment is directed to a method of a mobility management nodeof enabling delivery of a Mobile Terminating (MT) Short Message (SM), toa mobile terminal, which currently is in extended idle modediscontinuous reception (eDRX) mode.

The method comprising:

-   -   receiving an indication from a Short Message Service Gateway        Mobile Switching Centre (SMS-GMSC) that the SM is to be        delivered;    -   receiving a notification that the mobile terminal has exited the        eDRX mode before a paging occasion has occurred; and    -   submitting, in response to the notification, a message        indicating to the SMS-GMSC that the mobile terminal is available        for delivery of the SM.

Said message may be submitted directly to the SMS-GMSC.

Said message may be submitted to the SMS-GMSC via a Home SubscriptionServer (HSS).

The message submitted to the SMS-GMSC via the HSS may further comprisean instruction to the HSS to provide the destination address of themobility management to the SMS-GMSC.

The notification may be a Non-Access Stratum (NAS) request received fromthe mobile terminal.

The may further comprise: receiving, from the SMS-GMSC, the SM fordelivery to the mobile terminal.

The notification may be a context request received from a servingmobility management node of the mobile terminal, the method may furthercomprise: submitting, to the serving mobility management node, a contextresponse comprising an indication that the SM is to be delivered; andreceiving, from the serving mobility management node, a contextacknowledgement comprising a destination address of the serving mobilitymanagement node for SM delivery, wherein said submitted message furthercomprises the destination address of the serving mobility managementnode.

The notification may be a context request received from a servingmobility management node of the mobile terminal, said message beingsubmitted to the SMS-GSMC via the serving mobility management node in acontext response and further comprising a destination address of theSMS-GSMC.

The receiving of an indication from a SMS-GMSC that the SM is to bedelivered may comprise:

-   -   receiving an indication of maximum retransmission time        specifying how long the SMS-GMSC will store the SM if it cannot        be delivered at once and capability indication indicating if the        SMS-GMSC support receiving subsequent notification of mobile        terminal availability for delivering the SM; and the method        further comprising:    -   submitting an indication to the SMS-GMSC comprising a requested        retransmission time indicating at which point in time the SM        should be retransmitted by the SMS-GMSC and capability        confirmation that the mobility management node supports the        subsequent notification of mobile terminal availability for        delivering the SM.

A second embodiment is directed to a method of a mobility managementnode of enabling delivery of a Mobile Terminating (MT) Short Message(SM) to a mobile terminal, which currently is in extended idle modediscontinuous reception (eDRX) mode.

The method comprising:

-   -   receiving a notification that the mobile terminal has exited the        eDRX mode before a paging occasion has occurred;    -   submitting a context request to another mobility management node        by which the mobile terminal was served before the notification        was received;    -   receiving, from said another mobility management node, a context        response comprising an indication that the SM is to be        delivered; and    -   receiving, from the SMS-GMSC, the SM for delivery to the mobile        terminal.

Said message may be submitted directly to the SMS-GMSC.

Said message may be submitted to the SMS-GMSC via a Home SubscriptionServer (HSS), the message submitted to the SMS-GMSC via the HSS furthercomprises an instruction to the HSS to provide the destination addressof the mobility management to the SMS-GMSC.

Said message submitted further indicating a time period specifying thetime up until the mobile terminal again enters the eDRX mode.

Another embodiment is directed to a mobility management node configuredto enable delivery of a Mobile Terminating (MT) Short Message (SM) to amobile terminal, which currently is in extended idle mode discontinuousreception (eDRX) mode, and which mobility management node comprises aprocessing unit and a memory, said memory containing instructionsexecutable by said processing unit, whereby said mobility managementnode is operative to:

-   -   receive an indication from a Short Message Service Gateway        Mobile Switching Centre (SMS-GMSC) that the SM is to be        delivered;    -   receive a notification that the mobile terminal has exited the        eDRX mode before a paging occasion has occurred; and    -   submit, in response to the notification, a message indicating to        the SMS-GMSC that the mobile terminal is available for delivery        of the SM.

The mobility management node may be operative to submit the messagedirectly to the SMS-GMSC.

The mobility management node may be operative to submit the message tothe SMS-GMSC via a Home Subscription Server (HSS).

The mobility management node may further be operative to include aninstruction to the HSS to provide the destination address of themobility management to the SMS-GMSC in the message submitted to theSMS-GMSC via the HSS.

The notification may be a Non-Access Stratum (NAS) request received fromthe mobile terminal.

The notification may be a context request received from a servingmobility management node of the mobile terminal, further being operativeto:

-   -   submit, to the serving mobility management node, a context        response comprising an indication that the SM is to be        delivered; and    -   receive, from the serving mobility management node, a context        acknowledgement comprising a destination address of the serving        mobility management node for SM delivery, wherein said submitted        message further comprises the destination address of the serving        mobility management node.

The notification may be a context request received from a servingmobility management node of the mobile terminal, further being operativeto submit the message to the SMS-GSMC via the serving mobilitymanagement node in a context response and further to include adestination address of the SMS-GSMC.

The mobility management node may further be operative to, when receivingan indication from a SMS-GMSC that the SM is to be delivered:

-   -   receive an indication of maximum retransmission time specifying        how long the SMS-GMSC will store the SM if it cannot be        delivered at once and capability indication indicating if the        SMS-GMSC support receiving subsequent notification of mobile        terminal availability for delivering the SM; the method further        comprising: and    -   submit an indication to the SMS-GMSC comprising a requested        retransmission time indicating at which point in time the SM        should be retransmitted by the SMS-GMSC and capability        confirmation that the mobility management node supports the        subsequent notification of mobile terminal availability for        delivering the SM.

Another embodiment is directed to a mobility management node configuredto enable delivery of a Mobile Terminating (MT) Short Message (SM) to amobile terminal which currently is in extended idle mode discontinuousreception (eDRX) mode, and which mobility management node comprises aprocessing unit and a memory, said memory containing instructionsexecutable by said processing unit, whereby said mobility managementnode is operative to:

-   -   receive a notification that the mobile terminal has exited the        eDRX mode before a paging occasion has occurred;    -   submit a context request to another mobility management node by        which the mobile terminal was served before the notification was        received;    -   receive, from said another mobility management node, a context        response comprising an indication that the SM is to be        delivered; and    -   receive, from the SMS-GMSC, the SM for delivery to the mobile        terminal.

The mobility management node may further be operative to submit saidmessage directly to the SMS-GMSC.

The mobility management node may further be operative to submit saidmessage to the SMS-GMSC via a Home Subscription Server (HSS) the messagesubmitted to the SMS-GMSC via the HSS further comprising an instructionto the HSS to provide the destination address of the mobility managementto the SMS-GMSC.

The mobility management node may further be operative to include, insaid submitted message, a time period specifying the time up until themobile terminal again enters the eDRX mode.

Another embodiment is directed to a first computer program comprisingcomputer-executable instructions for causing a device to perform stepsrecited in the first embodiment when the computer-executableinstructions are executed on a processing unit included in the device.

Another embodiment is directed to a computer program product comprisinga computer readable medium, the computer readable medium having thefirst computer program embodied thereon.

Another embodiment is directed to a second computer program comprisingcomputer-executable instructions for causing a device to perform stepsrecited in the second embodiment summarized above when thecomputer-executable instructions are executed on a processing unitincluded in the device.

Another embodiment is directed to a computer program product comprisinga computer readable medium, the computer readable medium having thesecond computer program embodied thereon.

The invention has mainly been described above with reference to a fewembodiments. However, as is readily appreciated by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedpatent claims.

The invention claimed is:
 1. A mobility management node configured toenable delivery of a Mobile Terminating, MT, Short Message, SM, to amobile terminal, and which mobility management node comprises aprocessing unit and a memory, said memory containing instructionsexecutable by said processing unit, whereby said mobility managementnode is operative to: receive an indication from a Short Message ServiceGateway Mobile Switching Centre, SMS-GMSC, that the SM is to bedelivered to the mobile terminal, which is currently in extended idlemode discontinuous reception, eDRX, mode; receive a notification thatthe mobile terminal has exited the eDRX mode before a paging occasionhas occurred; and submit, in response to the notification, a messageindicating to the SMS-GMSC that the mobile terminal is available fordelivery of the SM; when receiving an indication from the SMS-GMSC thatthe SM is to be delivered: receive an indication of maximumretransmission time specifying how long the SMS-GMSC will store the SMif it cannot be delivered at once and capability indication indicatingif the SMS-GMSC support receiving subsequent notification of mobileterminal availability for delivering the SM; the method furthercomprising: and submit an indication to the SMS-GMSC comprising arequested retransmission time indicating at which point in time the SMshould be retransmitted by the SMS-GMSC and capability confirmation thatthe mobility management node supports the subsequent notification ofmobile terminal availability for delivering the SM.
 2. The mobilitymanagement node of claim 1, being operative to submit the messagedirectly to the SMS-GMSC.
 3. The mobility management node of claim 1,being operative to submit the message to the SMS-GMSC via a HomeSubscription Server, HSS.
 4. The mobility management node of claim 3,further being operative to include an instruction to the HSS to providethe destination address of the mobility management to the SMS-GMSC inthe message submitted to the SMS-GMSC via the HSS.
 5. The mobilitymanagement node of claim 1, the notification being a Non-Access Stratum,NAS, request received from the mobile terminal.
 6. The mobilitymanagement node of claim 1, the notification being a context requestreceived from a serving mobility management node of the mobile terminal,further being operative to: submit, to the serving mobility managementnode, a context response comprising an indication that the SM is to bedelivered; and receive, from the serving mobility management node, acontext acknowledgement comprising a destination address of the servingmobility management node for SM delivery, wherein said submitted messagefurther comprises the destination address of the serving mobilitymanagement node.
 7. The mobility management node of claim 1, thenotification being a context request received from a serving mobilitymanagement node of the mobile terminal, further being operative tosubmit the message to the SMS-GSMC via the serving mobility managementnode in a context response and further to include a destination addressof the SMS-GSMC.
 8. A mobility management node configured to enabledelivery of a Mobile Terminating, MT, Short Message, SM, to a mobileterminal, and which mobility management node comprises a processing unitand a memory, said memory containing instructions executable by saidprocessing unit, whereby said mobility management node is operative to:receive a notification that the mobile terminal has exited a extendedidle mode discontinuous reception, eDRX, mode before a paging occasionhas occurred; submit a context request to another mobility managementnode by which the mobile terminal was served before the notification wasreceived; receive, from said another mobility management node, a contextresponse comprising an indication that the SM is to be delivered; andreceive, from the SMS-GMSC, the SM for delivery to the mobile terminal.9. The mobility management node of claim 8, further being operative tosubmit said message directly to the SMS-GMSC.
 10. The mobilitymanagement node of claim 8, further being operative to submit saidmessage to the SMS-GMSC via a Home Subscription Server, HSS, the messagesubmitted to the SMS-GMSC via the HSS further comprising an instructionto the HSS to provide the destination address of the mobility managementto the SMS-GMSC.
 11. The mobility management node of claim 8, furtherbeing operative to include, in said submitted message, a time periodspecifying the time up until the mobile terminal again enters the eDRXmode.